Doing a sign and trade is tricky in his case. The question is, how much does the team you want to trade with want him, and, just who are they willing to trade? Is it someone you would want, or is it just a salary dump for them. Both of those things could be true by the way, but I wouldn't bet my life on it. First the Kings would have to retain his rights to keep him restricted. Second, another team would have to get him to sign an offer sheet. Then the negotiations would start. If they don't want to deal, then the only option we have left is to match their offer sheet in hopes that once we do that, they'll want to deal. But its a gamble. If they back away, guess what, we just resigned McLemore.
Personally, if the Kings aren't interested in retaining him, then I'd just let him walk. He's not Isaiah Thomas. The Kings would have had some leverage in his case. When you add to the equation that we don't have a lot of roster spots available, it would have to be someone we really want. What are the odd's of that? Not worth the trouble.